This invention relates to a camshaft operating system for an internal combustion engine, and more particularly to an improved drive arrangement for a multiple cam V-type overhead valve engine.
The advantages of twin overhead camshafts in improving engine performance are well known. However, the use of multiple camshafts for an engine, particularly when the engine is disposed at a V-arrangement, presents some problems. That is, all camshafts should be driven at one-half engine speed, and it is desirable to maintain a relatively simple and uncomplicated drive arrangement. Various arrangements have been proposed for V-type engines wherein one camshaft of each cylinder bank is driven from the crankshaft, and the driven camshaft drives the other camshafts through some form of mechanism. A wide variety of alternative arrangements have been proposed in the prior art for such drives.
However, with certain types of V-engines, it is also desirable to provide a balancer shaft arrangement for balancing the engine. This may be employed, for example, where the engine is designed so as to have the cylinder banks disposed at an angle other than the optimum angle at which even firing impulses result. When uneven firing impulses are employed, it is desirable to provide a balancer arrangement so as to compensate for these unbalanced forces. Of course, the drive for the balancer shaft and the location of the balancer shaft further complicates the arrangement.
It is, therefore, a principal object of this invention to provide an improved balancer camshaft drive arrangement for a multiple valve V-type engine.
It is a further object of this invention to provide an improved V-type of engine having a balancer shaft disposed in the valley between the cylinder banks and driven by the same drive that drives one camshaft of each cylinder bank.